Example embodiments relate to robotic arm assemblies. The robotic arm assembly may include forearm segment, upper arm segment, and elbow coupling joint assembly. Upper arm segment includes a motor. Elbow coupling joint assembly connects forearm and upper arm segments. Elbow coupling joint assembly includes distal and proximal elbow joint subassemblies. Distal elbow joint subassembly is connected to the forearm segment. Distal elbow joint subassembly includes gear train system having gear stages including first distal elbow gear stage, second distal elbow gear stage, third distal elbow gear stage, and fourth distal elbow gear stage. First distal elbow gear stage includes bevel gears. Second distal elbow gear stage includes spur gears. Third distal elbow gear stage includes bevel gears. Fourth distal elbow gear stage includes a planetary gear assembly. Proximal elbow joint subassembly connects the upper arm segment to the distal elbow joint subassembly.
